Conventionally, various devices for detecting target object(s) which transmit detection signals, receive reflection waves of the detection signals, and generate display image data of the detected target object(s) based on the reception signals, have been devised. Such target object detection devices have a problem caused by clutter, such as rain clutter. The clutter is such a phenomenon projected on a display screen that an amplitude value (intensity) of the reception signal becomes high except for the reflection waves from the target object(s). The rain clutter is one type of the clutter which is produced by the detection signals reflecting on rain.
Thus, JP2001-242246A, JP2003-172777A, and JP2002-243842A disclose target object detection devices which suppress the rain clutter by the radar apparatus indicated to.
The devices disclosed in JP2001-242246A and JP2003-172777A store a radar image in advance of a situation where it is not raining, compare it with a radar image obtained by the reception signals upon the target object detection to suppress the clutter.
Whereas, the device disclosed in JP2002-243842A suppresses the clutter by performing correlation processing between the current radar image and radar image obtained one antenna revolution before.
However, the conventional devices disclosed in JP2001-242246A, JP2003-172777A, and JP2002-243842A may be difficult to implement because the amount of data stored in advance becomes huge, or may be unable to effectively suppress the rain clutter according to the condition of rain.